Question

determine as raízes das equações:
a) 3x – 10 = 20 – 2x
b) 4. (x + 2) = 2x – 12
c) 5. (x - 4) = –2. (—x + 5)​

Answer 1

a)  3x-10=20-2x

    3x-10+10=20-2x+10

     3x=-2x+30

     3x+2x=-2x+30+2x

      5x=30

       5x                     30

     --------     =         ----------

        5                        5

      x=6

b)  4x+8=2x-12

    4x=2x-20

    4x-2x=2x-20-2x

    2x=-20

    x=-10

c)  

Answer 2

Resposta:

3× – 10 = 20 – 2×

3× + 2× = 20 + 10

5× = 30

× = $\frac{30}{5}$

× = 6

4. (× + 2) = 2× – 12

4× + 8 = 2× – 12

4× – 2× = – 8 – 12

2× = 20

× = $\frac{20}{2}$

× = 10

5. (x - 4) = –2. (—x + 5)​

5× – 20 = 2× – 10

5× – 2× = 20 – 10

3× = 10

× = $\frac{10}{3}$